Why do we need common sense in AI?
Commonsense knowledge is the collection of premises that everyone, in a certain context (hence common sense knowledge might be a function of the context), takes for granted. There would exist a lot of miscommunication between a human and an AI if the AI did not possess common sense knowledge. Therefore, commonsense knowledge is fundamental to human-AI interaction.
There are also premises that every human takes for granted independently of the country, culture, or, in general, context. For example, every human (almost since its birth) has a mechanism for reasoning about naive physics, such as space, time, and physical interactions. If an AI does not possess this knowledge, then it cannot perform the tasks that require this knowledge.
Any task that requires a machine to have common sense knowledge (of an average human) is believed to be AI-complete, that is, it requires human-level (or general) intelligence. See section D of AI-Complete, AI-Hard, or AI-Easy – Classification of Problems in AI (2012) by Roman V. Yampolskiy.
Of course, the problems that arise while humans communicate because of different assumptions or premises might also arise between humans and AIs (that possess commonsense knowledge).